Curable compositions comprising polyester resins and styrene have generally been epoxy polyester (vinyl ester) compositions wherein a portion of the polyester is replaced with styrene or other ethylenically unsaturated monomer. See, for example, U.S. Pat. No. 3,634,542.
Polyether resins and styrene blends are also known. These blends generally exhibit poor processability, short pot life, high viscosity and cure with conventional curing agents to produce products which do not exhibit good physical properties, such as high heat deflection temperatures and retention of physical properties at elevated temperatures. See, for example, U.S. Pat. No. 2,939,859 directed to a polyepoxide/styrene blend cured with peroxides and/or amines. While the compositions of U.S. Pat. No. 2,939,859 do exhibit a reduction of viscosity over an epoxy composition alone, the resulting products do not exhibit high heat deflection temperatures.
Other patents covering polyepoxide/styrene compositions include U.S. Pat. No. 3,099,638 and U.S. Pat. No. 3,009,898, which are directed to the use of anhydride curing agents, optionally in the presence of a peroxide and/or tertiary amine accelerator.
Epoxy/styrene blends which can be cured with a special curing agent/curing accelerator blend, e.g., an acid anhydride in combination with an onium salt, to yield products which exhibit improved physical properties, especially increased heat deflection temperatures and excellent retention of physical properties at elevated temperatures are disclosed and claimed in U.S. Pat. No. 4,284,753, issued Aug. 18, 1981.
Compositions of epoxy resin and (meth)acrylate esters of polyols are also known. See, for example, U.S. Pat. No. 4,010,289. The compositions of U.S. Pat. No. 4,010,289 are directed to a film coating which is cured via UV-radiation.
A composition has been found that exhibits high HDT's which comprises (1) an epoxy resin, (2) an ester of a ethylenically unsaturated monocarboxylic acid and styrene blend, (3) an aromatic amine and (4) a peroxide initiator.